This invention relates to an apparatus and method of using a simplified and scalable agricultural waste digester and biogas generation system. More specifically, this invention is directed to an agricultural waste digester with an agitation system that utilizes the force of trapped gas produced by the digester to further mechanically agitate the agricultural waste without additional energy added to the system such that the rising gas creates a mechanical force which induces agitation.
The use of anaerobic digestion techniques to obtain energy from agricultural and biological wastes has been known and utilized, at least to a limited extent, for years. However, recently the production of biogas from agricultural waste has gained a growing amount of interest for a number of reasons. Primarily, whereas biogas production from agricultural wastes such as animal manure and vegetation compost may have been of limited importance in terms of energy production and pollution control due to the smaller scale of farming operations in the past, today, as farming operations are becoming more technologically advanced and larger than ever in terms of the number of livestock, production, and waste volume, considerations involving pollution and energy use are becoming more important than ever. Notably, with modern scale concentrated animal feeding operations involving thousands or even tens of thousands of animals, the large production of waste volume has made biogas production not only a more viable option in terms of potential energy production, but also an important consideration in terms of pollution control, as such concentrated animal operations can generate large amounts of waste constituting a major threat to the environment, particularly with respect to water supplies, and air quality. Furthermore, apart from considerations attendant to large scale farming operations, the growing importance of the development and use of alternative, sustainable, and environmentally friendly energy sources in both developed and under-developed cultures has produced a renewed interest in the production of biogas from agricultural waste.
Although a variety of systems and devices have been developed to produce biogas from agricultural wastes such as animal manure or organic waste, the majority of known biogas production methods require large, costly components and employ a complicated system of tanks, valves, and the like. Furthermore, known systems either require the use of an agitator powered by a separate energy source and/or utilize rising bubbles of gas for agitation which flow freely through the organic waste carrying material and causing agitation which either require an additional energy source to operate an agitator or result in unpredictable and/or incomplete agitation. As a result, a need has arisen for a low-cost agricultural waste digester and biogas generation system that overcomes these problems.
Therefore a primary object of this invention is to provide an agricultural waste digester and biogas generation system that is scalable.
It is yet another object of this invention to provide an agricultural waste digester and biogas generation system that is simple and inexpensive to construct, operate, and maintain.
A further object of this invention is to provide an agricultural waste digester and biogas generation system that is versatile and effective in the production of biogas for any type of operation regardless of size and/or complexity, ranging from use in primitive, underdeveloped areas to large scale, modern concentrated animal feeding operations.
It is a further object of this invention to provide an agricultural waste digester and biogas generation system with a digester having an internal structure with no internal dead corners to provide more complete digester content mixing.
It is a further object of this invention to provide an agricultural waste digester and biogas generation system with a buoyant digester having an internal structure of a “reverse water wheel” which traps biogas on one side of the wheel and not the other to cause the digester to rotate in heated water without additional energy added to the system.
It is another object of this invention to provide an agricultural waste digester and biogas generation system which utilizes a power source operating via generated biogas to heat the water of the digester.
It is yet another object of this invention to provide an agricultural waste digester that has an internal structure which provides agitation and transport of organic/agricultural waste without the use of an agitator and additional energy added to the system.
It is still another object of this invention to provide an agricultural waste digester with arcuate, contoured interior segments which prevent biogas from moving freely out of the agricultural waste and trap biogas under these segments to utilize the force of the trapped biogas to rotate the digester and induce the agitation of agricultural waste and further production of biogas.
These and other objects, features or advantages of the present invention will become apparent from the specification and claims.